區塊鏈教程Fabric1.0源代碼分析consenter#filter
阿新 • • 發佈：2018-10-30
ror ews 2018年 fun .bat 筆記 range res 1.0 區塊鏈教程之Fabric1.0源代碼分析consenter（共識插件）#filter（過濾器），2018年下半年，區塊鏈行業正逐漸褪去發展之初的浮躁、回歸理性，表面上看相關人才需求與身價似乎正在回落。但事實上，正是初期泡沫的漸退，讓人們更多的關註點放在了區塊鏈真正的技術之上。
Fabric 1.0源代碼筆記 之 consenter（共識插件） #filter（過濾器）
1、filter概述
filter代碼分布在orderer/common/filter、orderer/common/configtxfilter、orderer/common/sizefilter、orderer/common/sigfilter、orderer/multichain目錄下。
orderer/common/filter/filter.go，Rule接口定義及emptyRejectRule和acceptRule實現，Committer接口定義及noopCommitter實現，RuleSet結構體及方法。
orderer/common/configtxfilter目錄，configFilter結構體（實現Rule接口）及configCommitter結構體（實現Committer接口）。
orderer/common/sizefilter目錄，maxBytesRule結構體（實現Rule接口）。
orderer/multichain/chainsupport.go，filter工具函數。
orderer/multichain/systemchain.go，systemChainFilter結構體（實現Rule接口）及systemChainCommitter結構體（實現Committer接口）。
2、Rule接口定義及實現
2.1、Rule接口定義
type Action int
const (
????Accept = iota
????Reject
????Forward
)
type Rule interface { //定義一個過濾器函數, 它接受、拒絕或轉發 (到下一條規則) 一個信封
????Apply(message *ab.Envelope) (Action, Committer)
}
//代碼在orderer/common/filter/filter.go2.2、emptyRejectRule（校驗是否為空過濾器）
type emptyRejectRule struct{} var EmptyRejectRule = Rule(emptyRejectRule{}) func (a emptyRejectRule) Apply(message *ab.Envelope) (Action, Committer) { ????if message.Payload == nil { ????????return Reject, nil ????} ????return Forward, nil } //代碼在orderer/common/filter/filter.go
2.3、acceptRule（接受過濾器）
type acceptRule struct{}
var AcceptRule = Rule(acceptRule{})
func (a acceptRule) Apply(message *ab.Envelope) (Action, Committer) {
????return Accept, NoopCommitter
}
//代碼在orderer/common/filter/filter.go2.4、configFilter（配置交易合法性過濾器）
type configFilter struct {
????configManager api.Manager
}
func NewFilter(manager api.Manager) filter.Rule //構造configFilter
//配置交易過濾器
func (cf *configFilter) Apply(message *cb.Envelope) (filter.Action, filter.Committer) {
????msgData, err := utils.UnmarshalPayload(message.Payload) //獲取Payload
????chdr, err := utils.UnmarshalChannelHeader(msgData.Header.ChannelHeader) //獲取ChannelHeader
????if chdr.Type != int32(cb.HeaderType_CONFIG) { //配置交易
????????return filter.Forward, nil
????}
????configEnvelope, err := configtx.UnmarshalConfigEnvelope(msgData.Data) //獲取configEnvelope
????err = cf.configManager.Validate(configEnvelope) //校驗configEnvelope
????return filter.Accept, &configCommitter{
????????manager: cf.configManager,
????????configEnvelope: configEnvelope,
????}
}
//代碼在orderer/common/configtxfilter/filter.go2.5、sizefilter（交易大小過濾器）
type maxBytesRule struct {
????support Support
}
func MaxBytesRule(support Support) filter.Rule //構造maxBytesRule
func (r *maxBytesRule) Apply(message *cb.Envelope) (filter.Action, filter.Committer) {
????maxBytes := r.support.BatchSize().AbsoluteMaxBytes
????if size := messageByteSize(message); size > maxBytes {
????????return filter.Reject, nil
????}
????return filter.Forward, nil
}
//代碼在orderer/common/sizefilter/sizefilter.go2.6、sigFilter（簽名數據校驗過濾器）
type sigFilter struct {
????policySource string
????policyManager policies.Manager
}
func New(policySource string, policyManager policies.Manager) filter.Rule //構造sigFilter
func (sf *sigFilter) Apply(message *cb.Envelope) (filter.Action, filter.Committer) {
????signedData, err := message.AsSignedData() //構造SignedData
????policy, ok := sf.policyManager.GetPolicy(sf.policySource) //獲取策略
????err = policy.Evaluate(signedData) //校驗策略
????if err == nil {
????????return filter.Forward, nil
????}
????return filter.Reject, nil
}
//代碼在orderer/common/sigfilter/sigfilter.go2.7、systemChainFilter（系統鏈過濾器）
type systemChainFilter struct {
????cc chainCreator
????support limitedSupport
}
func newSystemChainFilter(ls limitedSupport, cc chainCreator) filter.Rule //構造systemChainFilter
func (scf *systemChainFilter) Apply(env *cb.Envelope) (filter.Action, filter.Committer) {
????msgData := &cb.Payload{}
????err := proto.Unmarshal(env.Payload, msgData) //獲取Payload
????chdr, err := utils.UnmarshalChannelHeader(msgData.Header.ChannelHeader)
????if chdr.Type != int32(cb.HeaderType_ORDERER_TRANSACTION) { //ORDERER_TRANSACTION
????????return filter.Forward, nil
????}
????maxChannels := scf.support.SharedConfig().MaxChannelsCount()
????if maxChannels > 0 {
????????if uint64(scf.cc.channelsCount()) > maxChannels {
????????????return filter.Reject, nil
????????}
????}
????configTx := &cb.Envelope{}
????err = proto.Unmarshal(msgData.Data, configTx)
????err = scf.authorizeAndInspect(configTx)
????return filter.Accept, &systemChainCommitter{
????????filter: scf,
????????configTx: configTx,
????}
}
//代碼在orderer/multichain/systemchain.go3、Committer接口定義及實現
3.1、Committer接口定義
type Committer interface {
????Commit() //提交
????Isolated() bool //判斷交易是孤立的塊，或與其他交易混合的塊
}
//代碼在orderer/common/filter/filter.go3.2、noopCommitter
type noopCommitter struct{}
var NoopCommitter = Committer(noopCommitter{})
func (nc noopCommitter) Commit() {}
func (nc noopCommitter) Isolated() bool { return false }
//代碼在orderer/common/filter/filter.go3.3、configCommitter
type configCommitter struct {
????manager api.Manager
????configEnvelope *cb.ConfigEnvelope
}
func (cc *configCommitter) Commit() {
????err := cc.manager.Apply(cc.configEnvelope)
}
func (cc *configCommitter) Isolated() bool {
????return true
}
//代碼在orderer/common/configtxfilter/filter.go3.4、systemChainCommitter
type systemChainCommitter struct {
????filter *systemChainFilter
????configTx *cb.Envelope
}
func (scc *systemChainCommitter) Isolated() bool {
????return true
}
func (scc *systemChainCommitter) Commit() {
????scc.filter.cc.newChain(scc.configTx)
}
//代碼在orderer/multichain/systemchain.go4、RuleSet結構體及方法
type RuleSet struct {
????rules []Rule
}
func NewRuleSet(rules []Rule) *RuleSet //構造RuleSet
func (rs *RuleSet) Apply(message *ab.Envelope) (Committer, error) {
????for _, rule := range rs.rules {
????????action, committer := rule.Apply(message)
????????switch action {
????????case Accept: //接受
????????????return committer, nil
????????case Reject: //拒絕
????????????return nil, fmt.Errorf("Rejected by rule: %T", rule)
????????default:
????????}
????}
????return nil, fmt.Errorf("No matching filter found")
}
//代碼在orderer/common/filter/filter.go5、filter工具函數
//為普通 (非系統) 鏈創建過濾器集
func createStandardFilters(ledgerResources *ledgerResources) *filter.RuleSet {
????return filter.NewRuleSet([]filter.Rule{
????????filter.EmptyRejectRule, //EmptyRejectRule
????????sizefilter.MaxBytesRule(ledgerResources.SharedConfig()), //sizefilter
????????sigfilter.New(policies.ChannelWriters, ledgerResources.PolicyManager()), //sigfilter
????????configtxfilter.NewFilter(ledgerResources), //configtxfilter
????????filter.AcceptRule, //AcceptRule
????})
}
//為系統鏈創建過濾器集
func createSystemChainFilters(ml *multiLedger, ledgerResources *ledgerResources) *filter.RuleSet {
????return filter.NewRuleSet([]filter.Rule{
????????filter.EmptyRejectRule, //EmptyRejectRule
????????sizefilter.MaxBytesRule(ledgerResources.SharedConfig()), //sizefilter
????????sigfilter.New(policies.ChannelWriters, ledgerResources.PolicyManager()), //sigfilter
????????newSystemChainFilter(ledgerResources, ml),
????????configtxfilter.NewFilter(ledgerResources), //configtxfilter
????????filter.AcceptRule, //AcceptRule
????})
}
//代碼在orderer/multichain/chainsupport.go區塊鏈教程Fabric1.0源代碼分析consenter#filter